Japanese Patent Publication ( Publication No. Sho 60-50197 ) discloses that the compound of the formula [I] and salts thereof ( hereinafter called as Compound [I]) are excellent anti-allergic drugs. ##STR2##
But, ophthalmic application of Compound [I] has not been studied, so, it is necessary to examine preparation methods of ophthalmic formulations and study the effect on allergic eye diseases.
As the result of our precise studies on preparation methods of ophthalmic formulations and the effect on allergic eye diseases, we found that Compound [I] has an excellent anti-allergic effect in eyes and has a possibility to be applied to stable and low irritative ophthalmics.